为何要用getAbsolutePath呢？
public static boolean isMemoryEnough(File dir, long fileSize) {
StatFs stats = new StatFs(dir.getAbsolutePath());
long freeMem = (long) stats.getAvailableBlocks() * stats.getBlockSize();
freeMem *= 0.9;
return freeMem > fileSize;
}------解决方案--------------------
getAbsolutePath()获取的是路径，类型是不一样的